Explosive sealing heads for containers



Feb. 17, 1948.

C. J. M DOWELL EXPLOSIVE SEALING HEADS FOR CONTAINERS Filed Jan. 24, 1946 2 Sheets-Sheet 1 \N'VENTOR c.J.M DOWELL BY m Feb. 17, 1948. c. J. M DOWELL 2,435,364

EXPLOSIVE SEALING HEADS FOR CONTAINERS Filed Jan. 24, 1946 2 Sheets-Sheet 2 FIG. 2

27" esJ E g mvsmon V C-JMGD OWE LL Patented Feb. 17, 1948 EXPLOSIVE SEALING HEADS FOB CONTAINERS Creighton Joseph McDowell. Westmonnt. Quebec,

Canada, assignor to Dominion Merchants Company Limited, St. Laurent, Quebec, Canada Application January 24, 1946. Serial No. 843,178

6 Claims. (Cl. 220-89) 1 This invention relates to container sealing and discharging devices of the explosive sealing-head type.

The design of conventional explosive sealingheads used on fire extinguishers and other containers, requires complete replacement of the exploded head when the discharged container is turned in for recharging. This is due largely to the fact that the wall of the explosion chamber which is ruptured. by explosion of the explosive material constitutes an integral part of the main body portion of the head so that rupture of said wall makes it impractical to repair the head for re-use, and the only feasible alternative is the expensive one of substituting an entirely new head. a

A feasible and advantageous prior proposal for overcoming the foregoing objection consists in the provision of a separately formed blow-out plug assembly which is replaceably fitted in the main body portion of the head to provide an explosion chamber in which the explosion takes place, and provides a discharge opening by blowing out a portion of the replaceable plug assembly without damaging the more expensive main body portion of the head.

According to the above mentioned prior proposal, the body of the head is provided'with a cavity having a bottom opening serving both as a filling and discharge opening for the container, to which the head is applied. The replaceable blow-out plug assembly includes a stem comprising a solid portion and ,a cored out lower portion which are integrally joined together by a relatively thin frangible annular wall section. This stem is arranged in the cavity of the head with the cored out lower portion of the stem screwed into and closing said opening. A sleeve is screwed onto the solid upper portion of the stem so that the lower face of the sleeve forms the upper wall of an explosion chamber whose outer side wall is formed by the side wall of said cavity and whose remaining walls are formed by angularly related surfaces of said stem. The lower portion of the stem is cored out to provide a downwardly facing bore or cavity which is closed at the top by the solid upper portion of the stem and the frangible annular wall section which joins the two parts of the stem together. With this arrangement, the explosion of the explosive material contained in the explosion chamber results in the rupture of the thin wall section connecting the two parts of the stem and in the blowing out of the solid or upper part of the stem in such a manner that the lower or cored out part of the stem is left in place within'said opening in the form of an open ended tube through which the comtents of the container are discharged. This leaves the relatively more expensive body portion of the head in an undamaged condition and, when the container is turned in for recharging. that portion of the plug assembly which is left in the combined filling and discharge opening of the main body portion, may readily be removed to permit application of a new plug assembly to said body portion after the container has been recharged through said opening.

The above described proposal for combining a replaceable blow-out plug assembly with the main body portion of the head so that only the plug assembly is damaged by the explosion, has

as definite advantages over the conventional explosive head which is damaged beyond repair by fracture of the main body portion. However, as carried out in practice. this proposal for combining a replaceable blow-out plug assembly with the main body portion of the head, requires ex-' pensive manufacturing and assembly operations and has other disadvantages which the present invention proposes to eliminate by the provision of a simplified explosive sealing-head assembly having the same advantages as regards confining the destructive effects of the explosion to a plug assembly which is replaceably fitted in the main body portion of the head.

According to one feature of the present invention, the stem portion of the replaceable plug assembly associated with the main body portion of the head is redesigned to simplify manufacture thereof and to permit of its being more conveniently secured in place within the sealing head by means of a removable clamping nut.

According to another feature of the invention, the stem portion of the removable plug assembly associated with the main body portion of the head is redesigned to permit the detonator to be mounted in said stem portion instead of in the main body portion of the head as heretofore.

' A further feature of the invention consists in redesigning the blow-out plug assembly of the head so that the explosion chamber is enclosed solely by component parts of said assembly in- 3 stead of being partly enclosed by the main bodyportion of the head. as provided for in said prior proposal.

A further feature of the invention consists in providing an explosive sealing-head comprising a main body casting provided with a transverse partition having a central opening andlocated below the top'of the casting to form the bottom wall of a cavity in which a replaceable blow-out plug and detonator assembly is secured to seal said opening, said assembly comprising a sealing plug including a flange-like marginal portion bearing on a gasket arranged on the solid portion oi said partition and a central stem portion covering said opening and projecting above said flange-like marginal portion, a detonator fitted in a cavity which extends downwardly from the upper end of the stem and is connected by radial bores with an annular groove extending around the circumference of the stem above the flange-like marginal portion. a ring encircling the upwardly projecting portion of the stem and covering the groove to iorm'therewith an enclosed explosion chamber which. together with the bores, is filled with explosive material, a. flange projecting outwardly from the lower portion of the ring and resting on the flange-like marginal portion of the stem, and a ring-shaped clamping nut screwed into the upper portion of. the main casting and into clamping engagement with the flange of said ring, the lower end of said stem being cored out to provide a downwardly opening recess whose upper outer corner portion is separated from the inner lower corner portion of said groove by a thin wall section which is fractured by explosion of the explosive material contained in said explosion chamber. the fracture of said thin wall section permitting blowing-out of the portion of the stem closing the top of said recess to thereby provide a clear discharge opening defined by the side wall of the recess.

Other characteristic features and advantages of the invention will becomeapparent from the following detailed description of the accompanying drawings, in which:

Figure 1 is a vertical sectional view of my improved sealing-head assembly as it appears ap-.

plied to a container.

Figure 2 is a vertical sectional view of the main body portion of the sealing-head assembly shown in Figure 1.

Figure 8 is a vertical sectional view of an explosive sealing plug which is fitted in the main body portion of the sealing-head assembly to seal the discharge opening of the container.

Figure 4 is an eievational view of a sealing ring which is fitted over a stem portion of the sealing plug, shown in Figure I, to close a groove therein and thereby provide an enclosed explosion chamber in which explosive material is exploded to blow out a portion of the plug to provide a discharge opening through which the contents of the container is discharged.

Figure 5 is a sectional view of a ring-shaped clamping ring by means of which the sealing plug, shown in Figure 3, and the ring. shown in Figure 4, are clamped in place within the body portion shown in Figure 2.

Figure 6 is a vertical sectional view of a cap member which is associated with the body portion of the sealing-head after the sealing plug andlits groove-covering ring have been secured n p ace.

Referring more particularly to the drawings.

I designates a container sealed by an explosive sealing-head assembly I embodying my invention.

Assembly I includes a body member I comprising a lower internally threaded cricumierentiai wall portion I, an upper internally and externally threaded circumferential wall portion I, and an intermediate inwardly directed annular fiange. II located just above the internal thread of wall portion I. The inner edge of flange II defines a discharge opening II and is rounded ofl' as indicated at Ma. The upper surface of fiange II is provided with spaced circular sealing grooves II which are preferably V-shaped in cross section. 'The internal thread of wall portion I terminates an appreciable distance above flange II, leaving a smooth wall surface II between said thread and said fiange. Flange II provides, in eiieet, a centrally apertured partition extending transversely'across the bore of member I, and forming the bottom wall of a cavity in which a blow-out plug and detonator assembly A is re'placeably fitted-to seal the dischargeopening II..

The lower wall portion I of member I is screwed onto neck II of container I, so that flange II is seated agalnstthe Pi end of said neck. The upper wall portion I of member I is screwed into the internally threaded neck II of a hollow cap II. The internal cavity II of cap II is provided with a bottom inlet opening. bounded by neck II, and with a lateral discharge opening bounded by a lateral extension II or the cap member.

A sealing gasket II is compressed between the upper surface of flange II and an overlying flange-like marginal portion II of a sealing plug II. Portions of gasket II are forced downwardly into the sealing grooves II by circular V- shaped sealing ribs II depended from the aforesaid marginal portion II or plug II. The ceng tral portionof plug II comprises a piston-shaped stem II proiecting above the flange-like marginal portion II.. The outer circumferential surface of stem II is provided with acircular groove Ila affording the top, bottom and inner side walls of an enclosed explosion chamber II. the outer wall of which is formed by a ring I! which is a close sliding fit on stem II. Ring 21 is provided at its lowerend with an outwardly directed flange II which is clamped against the upper surface of the fiange like marginal portion II of plug II by an externally threaded ring-shaped clamping nut II, threaded engagement with the internal thread of wall portion I of body member I.

Stem Isis providedwith a detonator-receiving cavity'II extending downwardly from the upper end thereof. Stem II is also provided with bores II extending outwardly from the lower portion of cavity II to the groove IIa formed in the outer circumference oi said stem. A detonator II is threaded into stem cavity Ill and the bores II and'groo've Ila are filled with a suitable explosive-material such, for example, as cordite.

Detonator II may be included in a detonating circuitip any suitable manner. In the present instance, I have showna single wire II extending into the metal casing of the detonator but insulated therefrom by its insulation covering II. This wire is connected to one terminal'oi a source of current (not shown) by means of an outlet fitting I1 secured in a socket II of cap II by fastening screws I111. The insulation covered portion of. wire II is passed -to fitting I1 through a hole II provided in a wall portion of the cap separating socket II fromthe cap cavity II. The

other terminal of the electrical circuit is ground ed to the metal casing of the detonator in any suitable manner. 7

Stem 28 is cored out to provide a central bottom recess 4! of a diameter slightly greater than the inside diameter of groove a but appreciably less than the outside diameter of stem 2! as measured above or below the groove. Recess I is formed with a relatively shallow centre portion In and a relatively deep annular marginal portion lib. the depth of the marginal portion of the recess being appreciably greater than the thickness of the flange-like marginal portion 22 of sealing member 23. Recess ll is made shallow at its central portion to leave a suflicient section or thickness of metal below the detonatorreceiving cavity of stem 25. The diameter of recess II and the depth of the outer marginal portion lib are such as to leave only a relatively thin and frangible annular wall section 42 between the lower inner comer portion of groove 25a and the upper outercorner portion of recess 4 I.

When the explosive material contained in explosion chamber 26 and in the communicating bore 3| of sealing member 23 is exploded by det. onator 33, the thin wall section 42 of stem 3 is fractured and the upper portion of the stem. which normally forms the top of recess 4|, is blown away, thereby leaving the sealing member with a clear discharge opening defined by the annular side wall of recess 4|. The contents of the container are then discharged through this opening into cap cavity I8 andthence outwardly through the lateral discharge opening of cap II.

From the foregoing, it will be seen that sealing plug 22 is the only element of the sealing-head assembly which is destroyed by the explosion. This element, with its detonator, may be replaced at a relatively small cost compared with replacement of the entire sealing-head assembly. The invention. therefore, has definite economic advantages over previous types of container-sealing explosion heads which are substantially completely destroyed by the explosion. Another advantage of the invention is that the sealing plug, having the detonator assembled therewith, may be furnished as a unitary replacement assembly for the sealing plug and detonator of a discharged container, since the body I, clamping nut 29, and, in manycases, the ring 21 of the discharged container, are unimpaired by the explosion. Whenever necessary, the ring 21 may be included as part of the replacement assembly furnished for discharged containers. The combining of detonator I3 with sealing member 22 has important advantages, from both the manufacturing and replacement standpoint, as compared with prior types of container-sealing explosion heads in which the detonator is mounted in the main body portion of the sealing-head.

Having thus described the nature of my invention, and a preferred embodiment thereof, it will be understood that various modifications may be resorted to within the scope and spirit of the appended claims.

I claim:

1. An explosive sealing head for containers comprising a main body casting provided with a transverse partition having a central opening and located below the top of the casting to form the bottom wall of a cavity in which a replaceable blow-out plug assembly is secured to seal said opening, said assembly comprising a sealing plug including a flange-like marginal portion seated on said partition and a central stem portion covering the central opening in said artition and projecting above said flange-like marginal portion. said stem portion being formed with an outer circumferential groove located above said flange-like marginal portion and affording the top, bottom and inner side walls of an explosion chamber, a ring encircling the upwardly projecting part of the stem portion and covering said groove to form the outer wall of said explosion chamber, a flange projecting outwardly from the lower portion of said ring and resting on the flange-like marginal portion of the sealing plug, a ring-shaped clamping nut screwed into the upper portion of the main casting and into clamping engagement with the flange of said ring, said explosion chamber containin a charge of explosive material and the lower end of said stem being cored out to provide a downwardly opening recess whose upper outer corner portion is separated from the inner lower corner portion of said groove by a thin wall section which is fractured by explosion of said explosive charge and means for exploding said explosive charge.

2. An explosive sealing head for containers as set forth in claim 1, in which the means for igniting said charge of explosive material comprises a detonator fitted in a cavity which extends downwardly from the upper end of the stem portion of the sealing plug and is connected by radial bores with said explosion chamber.

3. An explosive sealing head assembly as set forth in claim 1, including a sealing gasket interposed between the upper surface of said transverse partition and the lower surface of the flange-dike marginal portion of said sealing plug, said flange-like marginal portion being provided with depending annular sealing ribs serving to depress portions of said gasket into underlying annular sealing grooves provided in said partition.

4. The combination with a container having an externally threaded neck portion of an explosive sealing head comprising a body member including upper and lower internally threaded circumferential wall portions and an intermediate, inwardly directed annular flange, said lower internally threaded wall portion being screwedonto said neck and said flange being seated against the end of said neck, a sealing plug fitted within the upper internally threaded wall portion of said body member to seal the opening defined by the inner edge of said flange, said plug including a flangelike marginal portion supported on said flange and a central stem portion projecting upwardly from said flange-like marginal portion and covering said opening, said stem-like portion being provided with an outer circumferential groove located above the flange-like marginal portion and forming the top, bottom and inner side walls of an explosion chamber, a ring encircling the upwardly projecting part of the stem portion of the plug and covering said groove to form the outer side wall of said explosion chamber, a flange projecting outwardly from the lower portion of the ring and resting on the flange-like marginal portion of the plug, a ring-shaped clamping nut screwed into the upper, internally threaded, circumferential wall of the body member and into clamping engagement with the flange of said ring, the lower end of the stem-like portion the sealing plug being cored out to provide a downwardly opening recess whose upper outer corner portion is separated from the inner lower comer portion of said groove by a thin annular wall section, a

greases charge of explosive material contained in said explosion chamber and means (or igniting said charge, the arrangement being such that the explosion or said charge in said explosion chamber serves to fracture said thin annular wall section and to blow-out the portion of the stem closing the top or said recess to thereby provide a clear discharge opening defined by the side wall oi the recess.

5. A sealing plug assembly comprising a sealing plug including a flange-like marginal portion and a central stem portion projecting above said.

flange-like marginal portion, said stem portion being provided with an outer circumferential groove located above said flange-like marginal portion and having its lower end cored out to provide a downwardly opening recess whose upper outer corner portion is separated from the inner lower corner portion or said groove by a thin annular wall section, a ring fitted on the upwardly projecting part of said stem portion and covering said groove, 9, flange projecting outwardly from said ring and resting on the flange-like marginal portion of the plug, said groove and ring conjointly defining an explosion chamber containing an explosive charge and means for lgniting said charge, the arrangement being such 8 that the explosion of said charge in said explosion chamber is eifected to disrupt the said thin annular wall section separating the inner lower corner portion of the groove from the upper lower corner portion of the recess.

6. A sealing plug assembly as set forth in claim 5, in which the means for igniting said explosive charge comprises a detonator fitted in a detonator recelvins cavity extending downwardly from the upper end of said stem portion, said detonator cavity being connected with said groove by radial bores formed in said stem portion and containing charges of explosive material.

CREIGHTON JQSEPH McDOWELL.

EEEEaENcEs crrEn The following references are of record in the file of this patent:

UNITED STATES PATENTS Germany Oct. 11, 1928 

